This core will provide centralized services and reagents to the research projects in the Program Project and will also provide shared instrumentation. As established in the prior proposal, the core will continue to provide large scale preparation of cultured cells, production of EGF receptor-rich vesicles from A-431 cells, preparation of mouse-derived EGF, preparation of 125I-EGF and 125I-protein A, and preparation of antisera. In addition, the core will expand its services to act as a repository and source of various vectors and the appropriate cell lines necessary for protein expression in either eukaryotic or prokaryotic systems. The core will provide technical support for initial protein expression studies and for large scale protein production and purification. In terms of instrumentation, the core will provide access to fermentation and centrifugation equipment for large scale protein expression, to a Phast Electrophoresis system for rapid protein detection, to a HPLC system for rapid, large scale protein purification, and the necessary technical assistance.